Series regulator



J. F. WALTON SERIES REGULATOR Feb. 7, 1967 Filed Jam 30, 1963 3 Sheets-Sheet l T B mm g m j E0 2 j lsoPLY I" 2 v B Q U 7. R D F U u 0 m 2 N U EEGUL RTED OUT PDT REGULATED OUTPUT 0 INVENTOR JOHN 'F. WALTON BY Wwm ATTORNEYS Feb. 7, 1967 J. F. WALTON 3,303,417

SER IE5 REGULATOR Filed Jan. 50, 1963 3 SheetsSheet 2 UNEEGULA ED INPUT [ZEGU L RTE D 6 OUTPUT f INVENTOF? JOHN T. LUALTON BY M.

ATTORNEY:

v Feb. 7, 1967 J. F. WALTON 3,303,417

SERIES REGULATOR Filed Jan. 30, 1963 5 Sheet heet 5 l g i7 .1 i 0 9 43 F: 6.6 v

2| 2 ea E 22 Y a3 uneesumeo u ur 1 QEGULQTED OUTPUT 0e l g log o7 1 5 J 405% INVENTOR MAI I I0"" JOHN F. wmn'ou BY M Z NL/ ATTORNEYS United States Patent 3,303,417 SERIES REGULATOR John F. Walton, McLean, Va., assignor, by mesne assignments, to Halliburton Company, a corporation of Delaware Filed Jan. 30, 1963, Ser. No. 254,898 20 Claims. (Cl. 323-22) The present invention relates generally to series regulator circuits and more particularly to series regulator circuits employing auxiliary voltage sources.

The so-called Victoreen high voltage regulator circuit has been utilized with a great deal of success in the range of 1 to 50 kilovolts. This highly eflicient circuit includes a series regulator tube in series with an unregulated source and a load as well as a single shunt path across the load. The shunt path consists of a dropping resistor connected in series with a Corona discharge voltage regulating or VR tube across which the input signal to the control grid of the series tube is derived. For varying input voltages, the current through, hence voltage across, the voltage regulator tube frequently changes materially. This is deleterious because the changes across the VR tube are in the same direction as those across the load. Thereby, the error voltage between the grid and cathode of the series tube is not adequate to provide the desired degree of regulation. For this reason, the Victoreen circuit is not adequate for precise regulation requirements.

According to the present invention, a floating voltage source having low noise content across its output terminals, such as disclosed in US. Patent No. 2,914,714 issued to John H. Reaves and John F. Walton, is connected in series aiding relation with the voltage across the aforesaid load at its high voltage side. This arrangement materially increases the total voltage across the current controlling or metering resistance. In consequence, the resistance value in the circuit can be considerably increased over that employed if the floating supply is excluded so that changes in voltage between the grid and cathode of the control tube are only a small percentage of the total voltage across the metering resistor. The increased resistance does not decrease the amount of VR tube current flow which remains, on the average, at the same level as with lower resistances because of the added voltage in the circuit. Therefore, the voltage across and current through the VR tube remain substantially constant even though wide variations occur at the load because most of the voltage from the load is coupled across the large resistor. It is desirable to maintain the current through a VR tube relatively constant because such a tube functions properly in a limited range and best in a very restricted sense; if the current varies outside of this range the voltage across the tube is either higher or lower than its rated value. The large resistor also tends to maintain the current through, hence voltage across, the VR tube substantially constant.

The present manner of employing an auxiliary voltage source is quite superior to that disclosed by Chapin in US. Patent No. 2,554,977. The circuit disclosed in that patent requires a pair of shunt paths, one for the gas voltage regulating tube and one for the necessary amplifier between the gas tube and the series regulator tube. For high voltage applications this is not feasible because excessive currents are bled through the regulator and reduce circuit efliciency.

Another feature of the present invention is that a pentode can be utilized as the series regulator tube by connecting its screen grid to the auxiliary supply. Utilization of pentodes with their high gain and great degree of isolation between control grid and plate has not been generally attainable in the past because of problems associated with screen grid bias. Bias for the screen grid has not been readily nor conveniently achieved through impedance voltage regulating means, such as VR tubes or Zener diodes, connected to the cathode of the series tube because such devices must have a certain current flow through them to achieve the desired results. This necessitates connecting a resistor between the control grid and plate. This resistor, in combination with the impedance regulator means, frequently causes the screen grid to be positive relative to the plate, an untolera ble situation in high power applications.

A further feature of the present invention is that an amplifier can be employed for deriving an error voltage indicative of the difference between a reference potential and the output without decreasing the efficiency of the circuit in coupling power between its input and output terminals. The amplifier may comprise a one or two tube circuit, depending upon the requirements for regulation, stabilization, efiiciency and economics.

If a one tube amplifier is utilized it may be a pentode having its control grid directly connected to the high voltage side of the load, its cathode connected to the VR tube and its anode connected through a load resistor and the auxiliary supply to the high voltage side of the load. The auxiliary supply also functions as the bias potential for the plate and screen grid of the amplifying pentode. According to one embodiment, sufiicient plate voltage is obtained through the use of a pair of separate floating supplies, between which the plate load for the amplifying pentode is connected to the control grid of the series tube. In another embodiment, a single supply having a center tap is employed, the positive terminal being connected to bias the screen grids of both the amplifier and series pentodes as well as the plate of the amplifier pentode, while the negative terminal is connected to bias the control grid of the series tube. These constructions do not require utilization of a shunt path across the load for biasing the control grid of the amplifier, hence have maximum efiiciencies.

If economics and not elficiency is the important factor, a triode amplifier may be substituted for the pentode. This triode requires lower plate potential so that the need for two separate or one tapped supply is obviated by utilizing a single untapped floating supply. To properly bias the triode, however, it is necessary to connect a tap from a voltage divider across the load to its grid. This, of course, reduces the efiiciency of the circuit because of the additional current path. However, for low voltage applications this is not a serious deterent because the VR tube frequently draws two to five times the current flowing through the divider.

To achieve an extremely stable, efiicient, and well regulated supply, a cathode coupled differential amplifier employing two tubes is employed. The control grids of the respective tubes are coupled to the high voltage side of the load and the VR tube. Thereby, an error voltage is derived at the plate of one of the tubes and is coupled back to the control grid of the series tube. Because all electrodes of both tubes are floating together due to their connections through floating supplies to the high voltage side of the load, the input impedance of the amplifier seen by the VR tube is virtually infinite, hence fails to load it. The floating arrangement for the differential amplifier tubes results in a regulator circuit having high gain and exceptional stability characteristics. High gain is achieved since the output load resistor for the differential amplifier can be selected to have a large value. D.C. stability is inherent in the negative feedback between the high voltage output to the electrodes of the differential amplifier through the floating supplies. Also, the floating supplies obviate the possibility of another shunt path asoaan 3 through the regulator. This is desirable because maximum efiiciency is achieved and because the requirement for high voltage tubes and high wattage resistors is eliminated in all control circuits except for the series regulator tube itself. I

According to a further embodiment of the invention, transistors are employed in such a manner that the only power transistor in the entire circuit is the one employed for series regulation. Each of the other transistors employed in the amplifier between the high voltage side of the load and the base or control electrode of the series transistor is of the conventional low power type because a floating supply is employed. The transistor in the coupling stage immediately preceding the series regulator transistor, instead of being connected in shunt with the unregulated input voltage as is the usual case, has its emitter-collector path biased by a floating supply. The floating supply is connected to bootstrap the high voltage side of the load to both the emitter and collector of the transistor in the coupling stage, whereby the need for a high voltage, power transistor in the coupling stage is eliminated. By floating the coupling stage transistor to the high voltage side of the regulator, large gains and great stability are achieved in the circuit controlling the VR tube. The bootstrapping feature also obviates the need for a high power resistor as the coupling stage load.

It is an object of the present invention to provide new and improved series regulator circuits employing auxiliary voltage sources.

Another object of the present invention is to provide new and improved series regulator circuits wherein fluctuations across voltage regulating devices are minimized.

An additional object of the present invention is to provide series regulator 'circuits having extreme regulating capabilities, great stability, high efliciency, yet are simple and inexpensive.

A further object of the present invention is to provide a series regulator employing high voltage power tubes or transistors only as the series control element, all other control devices being of the low voltage and power type.

An additional object of the present invention is to provide 'a new and improved series regulator wherein the amplifying circuit controlling the series control element has high gain and is very stable.

A further object of the present invention is to provide series regulator circuits employing amplifiers which draw little, if any, current from the unregulated power source.

The above and still further objects, features and advantages of the present invention will become apparent upon consideration of the following detailed description of several specific embodiments thereof, especially when taken in conjunction with the accompanying'drawings, wherein:

FIGURE 1 is a'circuit diagram of one embodiment of the present invention;

FIGURE 2 is a circuit diagram illustrating a modification of FIGURE 1 wherein a pentode is employed as the series regulator tube; 7

FIGURE 3 is a modification of FIGURE 2 wherein an amplifying pentode is employed to compare the voltages across a load and regulator tube;

FIGURE 4 is a modification of FIGURE 3 wherein a floating negative voltage supply is coupled from one end of the load to the control grid of the series regulator tube the bias said grid;

FIGURE 5 is a further modification of FIGURE 3 wherein a triode is employed as the amplifying element;

FIGURE 6 is another embodiment of the present invention wherein the 'load voltage is bootstrapped through floating supplies to the anode and cathode of a differential amplifier; and

FIGURE 7 is a further embodiment wherein the load voltage is bootstrapped through a pair of floating supplies to the electrodes of an amplifying transistor.

Reference is now made to FIGURE 1 of the drawings wherein an unregulated high voltage (1 to 50 kilovolts) source, of DC. voltage, such as derived by rectifying and filtering the power froman A.C. line, is coupled between positive terminal 11 and a common or ground lead 12 to a load connected across output terminal 13 and lead 12. Connected in series between terminals 11 and I3 is a series regulator tube, triode 14, having its anode 15 and cathode 16 connected directly to terminals 11 and 13, respectively. The negative terminal of DC. floating power supply 17 having very low capacitance to ground, such as shown in said Reaves et al, patent, is connected to terminal 13. The positive terminal of source 17 is connected to one end of resistor 18, the other end of which is connected to grid 19 of tube 14 and to the anode 21 of voltage regulator tube 22, of the Corona type. The cathode 23 of regulator or VR tube 22 is connected to ground 12 to complete the single shunt path in the regnla tor across the load.

In operation, the voltage across regulator 22 remains substantially constant despite wide variations in the load voltage between terminal 13 and ground 12. This is contrary to the normal operation of the circuit wherein supply 17 is excluded and variations in the current flowing through dropping resistor 18 materially change the voltage across tube 22. In the present invention, impedance 18 is of a large value, hence most of the load voltage drop occurs across it and not the'voltage regulator tube. It is possible to employ a large value for resistance 18 because supply 17, connected in series aiding relation with the load voltage, substantially increases the total available voltage across tube 22. Of course, it is desirable to maintain grid 19 at constant potential despite variations across the load and at cathode 16 to promote stability of series tube 14. Otherwise, there is the possibility of excessive voltage differences being developed between grid 19 and cathode 16 which might over drive tube 14 into saturation or cut-01f.

If it is assumed that the load Voltage between terminal 13 and ground rises above the desired regulated value because the-source connected to terminal 11 increases above its rated value, grid 19 which remains substantially constant relative to ground is driven negative relative to cathode 16. Hence, the impedance of variable element 114 between terminals 11 and 13 increases and the current supplied to the load decreases. This results in a decrease of load voltage back to the regulated value. The opera tion of variable impedance tube 14 is substantially the same for decreased load voltages but in the opposite direction.

FIGURE 2 is a modification of FIGURE 1 wherein pentode 24 is substituted for triode 14 to obtain a higher gain series impedance and one having substantial freedom at its control electrode from variations in the supply voltage. Anode 25, cathode 26, and control grid 27 of pentrode 24 are connected in the circuit in exactly the same manner as the corresponding elements of triode 14 in FIGURE 1. In addition, screen grid 28 is properly biased by its connection to the positive terminal of isolated supply 17.

It is not possible to utilize a pentode in conventional circuits wherein floating supply I7 is not employed. Impedance'volt'age regulating elements such as regulator tubes or Zener diodes, cannot be employed between the cathode and screen grid because they require a resistor to be connected between the screen and anode to carry the necessary current to establish the required bias. The connection of a resistor between the anode and screen, however, is not acceptable because the anode potential frequently drops below that of the screen.

Reference is now made to FIGURE 3 wherein an error signal deriving amplifier, pentode 31, is provided for effecting regulation of both high and low voltage sources. Bias for anode 32 of tube 31 is provided by the seriescircuit including floating supplies 1'7 and 33, between which is disposed load resistor 34 for plate 32.. Screen grids 35 and 28 of pentodes 31 and 24, respectively, are connected in parallel to be biased by supply 17. The control grid 36 and cathode 37 of pentode 31 are directly connected to load terminal 13 and anode 21 of voltage regulator tube 22, respectively, to control the current through plate 32.

In operation, the voltage across tube 22 at cathode 37 remains substantially constant despite variations of the input and output voltage because most of the load variations appear across the large combined impedances of tube 31 and resistance 34. If it is assumed that the voltage at terminal 11 decreases below the regulated value, the resulting drop in voltage at terminal 13 is coupled through supply 17 and resistor 34 with a tendency to drop the voltage at grid 27. This tendency is compensated by pentode 31, since its control grid 36 is simultaneously driven negative relative to its cathode 37. Hence, pentode 31 draws less plate current from supplies 17 and 33 and the voltage across load 34 decreases. This raises the voltage at control grid 27 of pentode 24 to compensate for the previously discussed drop and maintain the voltage at grid 27 substantially constant relative to ground. Since the cathode 26 of tube 24 has dropped relative to ground, control grid 27 is now biased more positively relative to the cathode than usually. Pentode 24 conducts more heavily and the regulated value of voltage across the load is again achieved.

Reference is now made to FIGURE 4 of the drawings wherein a single tapped power supply is employed in place of the two separate supplies 17 and 33 in FIG- URE 3. The positive and center terminals of supply 41 are connected to the circuit in exactly the same manner as supply 17 while the negative terminal of floating supply 41 is connected as a bias source for control grid 27 of series regulator tube 24 via dropping resistor 42. Bias for screen grid 35 is established at or below the voltage of plate 32 by dropping resistor 38, and the positive terminal of source 41. The output signal of pentode 31, developed across load resistor 34 is coupled to control grid 27 via a further dropping resistor 43.

In operation, any variations at terminal 13 from the regulated voltage are coupled directly to grid 36 and through the negative segment of source 41 and resistance 42 to grid 27. Due to the amplifying action of tube 31 in response to the error signal between its grid and cathode, the voltage across load resistor 34 is varied to compensate for the tendency of control grid 27 to change. Hence, grid 27 is maintained at a substantially constant potential and only the fluctuations at cathode 26 effect the series impedance, tube 24.

In each of the foregoing embodiments as well as in the embodiment of FIGURE 6, discussed infra, there is a single shunt path in the regulator across the load. For high voltage (1 kv. to 50 kv.) regulating purposes this is very desirable because there is a great degree of efficiency achieved, i.e., each hi h voltage shunt path draws considerable current from the source to materially reduce the power supplied to the load. If efficiency is not an important factor, however, the economical circuit of FIGURE 5 may be employed.

The circuit of FIGURE 5 is substantially like that of FIGURE 3 except that triode 51 has been substituted for pentode 31. As a result, the voltage for plate 52 is less than the voltage for plate 32 and supply 33 can be eliminated. The bias voltage for grid 53 must also be reduced, however, so the need for the voltage divider comprising resistors 54 and 55 and rheostat 56 arises. The slider of rheostat 56 is varied to properly bias grid 53, to which it is connected.

Bias for tube 24 is established in exactly the same manner as in FIGURE 3. In the circuit of FIGURE 5, however, grid 27 can possibly be driven positive relative to cathode 26 if there is a small enough voltage drop through resistor 34. To prevent this from occurring and preclude saturation of tube 24, limiter diode 57 has its 6 anode and cathode connected to grid 27 and cathode 26, respectively. For many uses there is no possibility of grid 27 exceeding the potential of cathode 26 and diode 57 can be eliminated.

Reference is now made to FIGURE 6 of the drawings wherein a highly stable, well regulated and efficient regulator employing a differential amplifier comprising pentodes 61 and 62 is illustrated. Bias energization for the electrodes of voltage regulator tube 22 and series pentode 24 are established in the same manner as illustrated in FIGURE 3. In addition, negative biasing for cathodes 64 and 65 of tubes 61 and 62 is established through cathode resistor 63 and supply 66. The voltage at terminal 13 is directly coupled to control grid 67 of pentode 61 and is bootstrapped to cathodes 64 and 65 via supply 66 and resistor 63. Biasing for plate 68 of pentodes 62 and screen grids 69 and 70 of both tubes in the differential amplifier is established by direct connections to the positive terminal of supply 17. Anode 72 of tube 61 is connected to the positive terminal of floating bias supply 73 which is connected in series aiding relation with supply 17 via resistance 74, the plate load for pentode 61. It is thus seen that all biasing for the tubes in the differential amplifier is through floating supplies. Since no shunt paths across the load for amplifier tube energization are employed, efiiciency of the regulator is extremely high and the need for high voltage tubes in the differential amplifier is obviated even if the input at terminal 11 is in the l to 50 kv. range.

In operation, the voltage across regulating tube 22, hence at control grid 75 of pentode 62, is maintained substantially constant, as described in connection with FIGURE 1, supra. Variations in the voltage at terminal 13 are coupled to grid 67 and compared with the constant voltage at grid 75 through the action of cathode resistor 63. These variations result in changes in the plate current supplied to pentode 61, hence vary the voltage across resistance 74 and at control grid 27 to maintain the voltage of terminal 13 constant. For example, if it is assumed that the voltage at terminal 13 increases, the current through pentode 61 and voltage across resistor 74 also increase. The larger drop across resistance 74 compensates for the higher potential coupled through supply 17 from terminal 13 so that the voltage at control grid 27 is maintained substantially constant. Hence, control grid 27 is now biased more negatively with respect to cathode 26 and the impedance of tube 24 is reduced, as is the load voltage back to the regulated value.

Reference is now made to FIGURE 7 of the drawing wherein the bootstr-appin techniques of FIGURE 6 are employed to obtain a regulator requiring a single power transistor 81, having its collect-or 84 and emitter 85 connected to unregulated and regulated negative D.C. voltages at terminals 62 and 83, resepectively. The control electrode or base 86 of PNP transistor 81 is responsive to voltage variations at the emitter 87 of PNP transistor 88, which maybe of the conventional low power type because there are no currents between terminal 82 and ground flowing through it. This is because its emitter collector path is biased by tapped floating supply '89, the negative and center taps of which are connected to collector 9-1 of transistor 88 and terminal 83, respectively. The positive terminal of supply 89 is coupled to emitter 87 via resistor 92, the load for transistor 88. Resistor 5 2 can be of the low wattage type since it carries only small currents. If transistor 88 were energized in the normal fashion, i.e., with its collector and emitter between ground and terminal 82, large currents would flow through it and resistor 92, necessitating the utilization of components having correspondingly rated values.

To control the signal coupled to base 93 of transistor 88, differential amplifier 94 and amplifying PNP transistor 97 are employed. Differential amplifier 94 comprises a pair of PNP transistors 95 and 96 having their emitters connected together to a positive reference voltage at terminal 11d via resistor 98. The collectors of transistors 5 and 96 are connected together through separate load resistors lliil and 102 to the negative bias supply between ground and terminal 103. Base bias for transistor 95 is established by the voltage divider between terminals 83 and 11d comprising rheostat 1G4 and resistor 105. The base of transistor 96 is connected directly to ground so that the voltage at its collector is always indicative of the difference between terminal 83 and a reference potential.

To enable wide variations in the voltage at terminal 83 to be selected, in the range off) to 80 volts, it is necessary that the bases of transistors $5 and 96 always be forward biased relative to their emitters. This is accomplished by supplying a positive votage to terminal 110 by means of a DC. source connected between terminal 106 and ground. To insure adequate regulation at terminal 119, Zener diodes 1&7 and 108 are connected between ground and the voltage divider comprising resistors 199 and Ill, coupled between terminals llltl and 1%.

The output signal of differential amplifier 94 derived at the collector of transistor 96 is coupled to the base of amplifying transistor 97. Collector-emitter bias for transistor 97 is established by the path from terminal 83 through the negative segment of supply 89 and resistor 112 to the collector and through the load at terminal 83 to the emitter. Resistance 112 is the collector load for transistor 97 which enables the variable control voltages for transistor 88 to be derived.

In operation, with rated voltage applied to terminal 82 and a rated load connected to terminal 83, the slider of potentiometer 194 is adjusted to obtain the desired voltage across the load. As the input voltage at terminal 82 increases above its rated value, the base of transistor 95 becomes more forward biased than usual in response to the larger voltage at terminal 83. This causes more current to fiow through transistor 95 and increases the voltage across resistor 98. The increased voltage across resistor 98 is coupled to the emitter and collector of transistor 95. In response to the larger voltage at the collector of transistor 96, the base of transistor 97 becomes more forwardly biased so that the collector voltage thereof decreases. The lower amplitude voltage at the collector of transistor 97 compensates for the increased voltage at terminal 83 which is coupled through the negative part of supply 8? and resistor 112 to base 93 of transistor 88. Thereby, the base 93 has a tendency to remain at substantially constant potential which is reflected to base 86 of series regulating transistor 31 via emitter 87. Hence, any tendency for emitter 85 to rise above the rated value causes the impedance of transistor 81 to rise in a cornpensating manner to restore the regulated output voltage. It is to be understood that the circuitfunctions in a similar but oppositely directed manner if the amplitude of the output voltage decreases below the rated value.

While I have described and illustrated one specific embodiment of my invention, it will be clear that variations. of the details of construction which are specifically illustrated and described may be resorted to without departing from the true spirit and scope of the invention as defined in the appended claims.

What I claim is: V

1. A regulator circuit for coupling a source of unregulated DC. power to a load comprising a variable impedance, said impedance having a first electrode for emitting charged carriers, a second electrode for receiving said charged carriers, and a third electrode for controlling the flow of said charged carriers between said first and second electrodes, said first and second electrodes being connected in series between said source and said load, only one current path connected across said load for maintaining the potential applied to said third electrode substantially constant despite variations of the load voltage, said path comprising in series: an impedance element for deriving a substantially constant voltage only when the voltage across it is approximately equal toor exceeds the value of said constant voltage, a dropping impedance, and a source of potential in series aiding relationship with the voltage across said load.

2. A regulator circuit for coupling a source of unregulated DC. power to a load comprising an electron discharge tube having an anode, cathode, and control grid, said anode and cathode connected in series between said source and said load, only one current path connected across said load for maintaining the potential applied to said control grid substantailly constant despite variations of the load voltage, said path comprising in series: a voltage regulator tube, a dropping impedance, and a source of potential in series aiding relationship with the voltage across said load, said control grid being connected to a predetermined point in said path.

3. The regulator circuit of claim 2 wherein said electron discharge tube is a triode. V

4. The regulator circuit of claim 2 wherein said electron discharge tube further includes a screen grid connected to a higher potential point in said path than said predetermined point.

5. The regulator circuit of claim 2 wherein said path includes means for maintaining the current in said path substantially constant despite variations of the voltage across said load.

'6. The regulator circuit of claim 5 wherein said means for maintaining includes an electron discharge tube having its anode and cathode connected in series with said path and its control grid coupled to said load.

7. A regulator circuit for coupling an unregulated DC. power source to a load, comprising a common connection for one side of said source and one side of said load, a variable impedance element having a first electrode for emitting charged carriers, a second electrode for receiving said charged carriers, and a third electrode for controlling the flow of said charged carriers between said first and second electrodes, said first and second electrodes being connected to the other sides of said load and said source, respectively, means for maintaining the potential applied to said third electrode substantially constant despite variations in the potential across said load, said means for maintaining including a current path connected across said load, said path including, an impedance element for deriving a substantially constant voltage only when the voltage across it is approximately equal to or exceeds the value of said constant voltage, one end of said element being connected to said common connection, a dropping impedance, and a source of potential connected in a series circuit between the other end of said element and said other side of said load, said element being connected across said load only via the series circuit including said source, said potential source being in series aiding relationship'with the voltage across said load.

8. The regulator circuit of claim 7 wherein said series circuit includes means for maintaining the current in said path substatially constant despite variations of the voltage across said load.

9. The regulator circuit of claim 8 wherein said current maintaining means includes an electric discharge device having a fourth electrode for emitting charged carriers, a

fifth electrode for receiving the carriers from said fourth electrode, and a sixth electrode for controlling the flow of said carriers between the fourth and fifth electrodes, said sixth electrode being responsive to the potential across said load, said fourth electrode being responsive to the voltage at said other end of said element, said fifth electrode being connected in series with said potential source and said dropping impedance.

it). The regulator circuit of claim 9 wherein; said variable impedance element includes another electrode disposed between said second and third electrodes, said electric dicharge device includes a further electrode disposed between said fifth and sixth electrodes, said potential source is divided into two segments having said dropping impedance connected th-erebetween, means for connecting 9 the potential from said first segment to said further and another electrodes, and means for connecting the potential from said second segment to said fifth electrode.

11. The regulator circuit of claim 7 wherein said vari able impedance element includes a further electrode disposed between said second and third electrodes, and means for coupling a biasing voltage from said potential source to said further electrode.

12. The regulator of claim 7 wherein said means for maintaining further includes means for deriving an error signal indicative of the difference between the voltage across said impedance element and said load, and means for coupling said error signal to said third electrode.

13. The regulator of claim 12 wherein said error signal deriving means includes an amplifier having a fourth electrode for emitting charged carriers and a fifth electrode for receiving said carriers, a floating potential source coupled between said other side of said load and said fourth electrode for biasing said fourth electrode, said error signal being derived at said fifth electrode.

14. The regulator of claim 12 wherein said error signal deriving means includes a first and a second electric discharge means, each having an emitter of charged carriers, a collector for said carriers, and a control electrode for said carriers, a floating potential source coupled between the other side of said load and a common junction for said emitters for biasing said emitters, the control electrodes of said first and second discharge means being connected to the other sides of said load and impedance element, respectively, the collector of said second discharge means being connected to a point in said series circuit to bias it to receive carriers from the emitter of said second discharge means, a load for the collector of said first discharge connected between a point in said series circuit and said third electrode, and means for coupling said error signal derived at the collector of said first discharge means to said load.

15. The regulator of claim 14 including a further floating potential supply coupled between the collector of said first discharge means and said load, said further floating supply being of such polarity and amplitude as to bias the collector of said first discharge means.

16. The regulator of claim 15 wherein said variable impedance element includes a further electrode disposed between said second and third electrodes, each of said electric discharge means including another electrode dis posed between said control electrode and said collector, said another and further electrodes being connected to said series circuit to be biased to receive said carriers.

17. A regulator circuit for coupling a source of unregulated D.C. power to a load comprising: a variable impedance electronic device having an emitting electrode, a receiving electrode, and a control electrode; means connecting said emitting and receiving electrodes in series between said source and said load; current path means connected across said load for maintaining the potential applied to said control electrode substantially constant despite load voltage fluctuations, said current path means comprising: an impedance element for deriving a substantially constant voltage across its terminals only when a current of minimum amplitude is maintained through said element, a metering impedance of sulficient magnitude to absorb substantially all of the load voltage fluctuations thus preventing said fluctuations from materially altering current flow through said element, and a source of potential of at least sufiicient magnitude so to maintain a current through said impedance element of said minimum amplitude.

18. The regulator circuit of claim 17 additionally comprising means for supplying an error signal indicative of the difference between the voltage across said load and a reference voltage to said control terminal, said means for supplying including an electric discharge device having an emitter electrode of charged particles and a collector electrode for said particles, means, including a floating biasing potential source for said electrodes, for coupling the voltage at said one end of said load to said electrodes, said error signal being derived in response to the voltage between said electrodes.

19. The regulator circuit of claim 17 additionally comprising means for supplying an error signal indicative of the difference between the voltage across said load and a reference voltage to said control terminal, said means for supplying including an electric discharge device having an emitter electrode of charged particles and a collector electrode for said particles, a load impedance connected in series with the collector-emitter path of said discharge device, a floating biasing supply connected in series with said path for coupling the voltage at said one end of said load to one of said electrodes, means for coupling the voltage at said one end of said load to the other of said electrodes, and means including said source of potential for coupling the voltage across said load impedance to said control terminal.

20. The combination as set forth in claim 17 wherein said variable impedance electronic device is a pentode.

References Cited by the Examiner UNITED STATES PATENTS 2,774,032 12/1956 Burdge 323-22 2,866,017 1'2/1958 Jones. 2,912,638 11/1959 McNamee.

FOREIGN PATENTS 698,687 10/1953 Great Britain.

JOHN F. COUCH, Primary Examiner. LLOYD MCCOLLUM, Exa'miner. G. P. HAAS, K. D. MOORE, Assistant Examiners. 

7. A REGULATOR CIRCUIT FOR COUPLING AN UNREGULATED D.C. POWER SOURCE TO A LOAD, COMPRISING A COMMON CONNECTION FOR ONE SIDE OF SAID SOURCE AND ONE SIDE OF SAID LOAD, A VARIABLE IMPEDANCE ELEMENT HAVING A FIRST ELECTRODE FOR EMITTING CHARGED CARRIERS, A SECOND ELECTRODE FOR RECEIVING SAID CHARGED CARRIERS, AND A THIRD ELECTRODE FOR CONTROLLING THE FLOW OF SAID CHARGED CARRIERS BETWEEN SAID FIRST AND SECOND ELECTRODES, SAID FIRST AND SECOND ELECTRODES BEING CONNECTED TO THE OTHER SIDES OF SAID LOAD AND SAID SOURCE, RESPECTIVELY, MEANS FOR MAINTAINING THE POTENTIAL APPLIED TO SAID THIRD ELECTRODE SUBSTANTIALLY CONSTANT DESPITE VARIATIONS IN THE POTENTIAL ACROSS SAID LOAD, SAID MEANS FOR MAINTAINING INCLUDING A CURRENT PATH CONNECTED ACROSS SAID LOAD, SAID PATH INCLUDING, AN IMPEDANCE ELEMENT FOR DERIVING A SUBSTANTIALLY CONSTANT VOLTAGE ONLY WHEN THE VOLTAGE ACROSS IT IS APPROXIMATELY EQUAL TO OR EXCEEDS THE VALUE OF SAID CONSTANT VOLTAGE, ONE END OF SAID ELEMENT BEING CONNECTED TO SAID COMMON CONNECTION, A DROPPING IMPEDANCE, AND A SOURCE OF POTENTIAL CONNECTED IN A SERIES CIRCUIT BETWEEN THE OTHER END OF SAID ELEMENT AND SAID OTHER SIDE OF SAID LOAD, SAID ELEMENT BEING CONNECTED ACROSS SAID LOAD ONLY VIA THE SERIES CIRCUIT INCLUDING SAID SOURCE, SAID POTENTIAL SOURCE BEING IN SERIES AIDING RELATIONSHIP WITH THE VOLTAGE ACROSS SAID LOAD. 